In endoscopic surgery (also referred to as “laparoscopic surgery”), plural holes are drilled into the abdomen of a patient, and after a trocar (cylindrical instrument) is inserted into the holes, a laparoscope (camera) and a plurality of forceps are inserted into a body cavity through each trocar. Grippers, scissors, or blades of an electrosurgical knife, for gripping biological tissues are mounted on the tips of the forceps as an end effector. If the laparoscope and the forceps are inserted into the body cavity, an operator operates the forceps while viewing a state of the inner portion of the abdominal cavity, which is shown on the monitor connected to the laparoscope. Since the surgical procedure does not require a laparotomy, the patient burden is decreased, which reduces the number of days for postoperative recovery and leaving the hospital.
General forceps that do not have a joint at the tip, and forceps that have a plurality of joints at the tip and change a posture of the tip are called a medical manipulator. (See for example, Japanese Patent Application JP-A-2004-105451). With the medical manipulator, an operation having a relatively high degree of freedom can be performed in the body cavity. In addition, the manipulation is relatively easier and applicable cases are increased with the medical manipulator. The medical manipulator disclosed in JP-A-2004-105451 includes a working unit that includes a tip operating unit having an end effector and a joint and an operating unit having a drive mechanism for driving the tip operating unit. The drive mechanism includes an actuator for changing the posture of the tip operating unit and an actuator for opening and closing the end effector and drives each of the actuators according to the operation with respect to an operation input unit that is provided in the operating unit, and the tip operation unit is operated.
When the operation is mechanically transmitted by hands and the opening and closing of the tip are performed in general with forceps that do not have a joint at the tip, the operator can perceive a gripping force acting on the tip. However, in the medical manipulator of JP-A-2004-105451, since all operations of the tip operating unit are performed by the driving of the actuator, an operator cannot directly perceive the gripping force that acts on the tip operating unit.